Method and device for provisioning bidirectional filter in pfd management procedure

ABSTRACT

The present disclosure provides methods and apparatuses for provisioning a bidirectional filter. In some embodiments, a method of a first network entity performing a session management function (SMF) in a communication system includes obtaining a first filter for a first direction and a second filter for a second direction that are associated with an application, identifying whether the first filter is a bidirectional filter based on a result of comparing the first filter and the second filter, identifying whether a second network entity performing a user plane function (UPF) supports a function of obtaining the second filter, based on the first filter being identified as the bidirectional filter, and transmitting, to the second network entity, a first message including the first filter and information indicating that the first filter is the bidirectional filter, based on identifying that the second network entity supports the function of obtaining the second filter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of InternationalApplication No. PCT/KR2021/003158, filed on Mar. 15, 2021, which claimspriority to Korean Patent Application No. 10-2021-0033158, filed on Mar.15, 2021, in the Korean Intellectual Property Office, the disclosures ofwhich are incorporated by reference herein in their entireties.

BACKGROUND 1. Field

The present disclosure relates generally to an operation between asession management function (SMF) of a control plane and a user planefunction (UPF) of a user plane in a core network of a next-generationmobile communication system. More particularly, the present disclosurerelates to a method for the SMF providing a filter for detectingapplication traffic to the UPF.

2. Description of Related Art

Efforts may be being made to develop an improved 5th generation (5G)communication system and/or a pre-5G communication system that may meetan increasing demand for wireless data traffic after commercializationof a 4th generation (4G) communication system. For this reason, a 5Gcommunication system and/or a pre-5G communication system may bereferred to as a communication system after the 4G network (e.g., Beyond4G Network) and/or system after the Long Term Evolution (LTE) system(e.g., Post LTE). In order to potentially achieve a high data rate, arelated 5G communication system may be considered for implementation ina super high frequency band (e.g., such as, but not limited to, a 60gigahertz (GHz) band, a millimeter wave (mmWave) band (e.g., 24-300GHz), and/or an extremely high frequency (EHF) band).

However, such frequency bands may typically exhibit a higher path lossand/or a decreased transmission distance, when compared to otherwireless communication systems. As such, related 5G communicationsystems may attempt to alleviate the path loss of radio waves in thesuper high frequency band and/or increase the transmission distance ofradio waves by employing techniques, such as, but not limited to,beamforming, massive multiple-input multiple output (MIMO), fulldimensional MIMO (FD-MIMO), array antennas, analog beam-forming, and/orlarge scale antenna technologies.

Alternatively or additionally, the related 5G communication systems mayattempt to improve the network architecture of the system by employingtechnologies such as, but not limited to, evolved small cell, advancedsmall cell, cloud radio access network (cloud RAN), ultra-dense network,device-to-device communication (D2D), wireless backhaul, moving network,cooperative communication, coordinated multi-points (CoMP), interferencecancellation, and the like. Furthermore, the related 5G communicationsystems may employ an advanced coding modulation (ACM) method (e.g.,hybrid frequency shift keying (FSK) and quadrature amplitude modulation(QAM) modulation (FQAM), sliding window superposition coding (SWSC),and/or an advanced connection technology (e.g., filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), sparse codemultiple access (SCMA), and the like).

Meanwhile, the Internet may be evolving from a human-centered network inwhich humans may generate and consume information to an Internet ofThings (IoT) network that may exchange and/or process informationbetween distributed components (e.g., an object, and the like). Internetof Everything (IoE) technology, which may combine big data processingtechnology, and the like through connection with a cloud server, and thelike with IoT technology, may also be emerging. In order to implementIoT devices and/or networks, technology elements such as sensingtechnology, wired and wireless communication and network infrastructure,service interface technology, and security technology may be needed. Tothat end, technologies for connections between objects such as, but notlimited to, a sensor network, machine-to-machine (M2M) communication,and machine type communication (MTC), and the like, may have beenexplored.

For example, an IoT environment may provide an intelligent internettechnology service that may create a new benefit in human activities bycollecting and/or analyzing data generated from connected objects. Assuch, IoT environments may be applied to a variety of fields such as,but not limited to, smart homes, smart buildings, smart cities, smartand/or connected cars, smart grids, health care, smart home appliances,advanced medical services, and the like, through convergence and/orcombination between an existing information technology and variousindustries.

Accordingly, attempts may be made to apply a 5G communication systemand/or technologies to an IoT network. For example, technologies suchas, but not limited to, sensor networks, M2M communication, MTC, and thelike may be implemented by using techniques such as, but not limited to,beamforming, MIMO, array antennas, and the like, which may have beenoriginally developed as 5G communication technologies. The applicationof a cloud cloud RAN as a big data processing technology may be anotherexample of the convergence of 5G technology and IoT technology.

Meanwhile, in line with the above-described technical developments, astructure of a core network of the communication system may have beendiscussed. For example, in an existing LTE communication system, amobility management entity (MME) may be responsible for a mobilitymanagement function and a session management function, a packet datanetwork gateway (P-GW) that may perform functions such as, but notlimited to, delivering packets between a terminal and an external packetdata network (PDN), charging according to data usage, and the like, anda serving gateway (S-GW) that may perform functions such as, but notlimited to, routing user packets between a base station and the P-GW,and the like, may configure an evolved packet core (EPC), which may bereferred to as a core network. Since the MME, the P-GW, and the S-GWconfiguring the EPC may be network entities in which a control planefunction and a user plane function may be closely combined, flexiblenetwork management may be difficult.

Meanwhile, telecommunication standards (e.g., Third GenerationPartnership Project (3GPP) Release 14) may promulgate a structure ofcontrol and user plane separation (CUPS) that may separate the controlplane and the user plane of the P-GW and the S-GW of the EPC using asoftware defined network (SDN) technology. Subsequently, the CUPSstructure may be applied to the structural design of the 5G core network(5GC). Consequently, separation between the control plane and the userplane may be achievable in the 5G core network. That is, the separationbetween the control plane and the user plane may be achieved as thestructure in which authentication, access control, and mobility controlfunctions of EPC MME may be performed by the 5GC access and mobilitymanagement function (AMF), in terms of the control plane, the sessionmanagement function of the EPC MME may be performed by the 5GC sessionmanagement function (SMF), and packet processing, and the like of theEPC GW may be performed by the 5GC user plane function (UPF) in terms ofthe user plane.

Accordingly, exists a need for further improvements in methods forreducing the function and implementation complexity of the AMF and theSMF processing the control plane, the UPFs processing the user plane,and the signaling load between network entities.

In the above-described related 5GC, an SMF of a control plane mayprovide a plurality of filters to the UPF so that a UPF of a user planemay detect application traffic. In a related 5G communication system,the number of applications that may be serviced may have increasedsignificantly when compared to an existing LTE communication system.Alternatively or additionally, as a traffic type of the aboveapplication may have also diversified, the number of filters to bedefined in order to detect one application may have increasedsignificantly. However, since the length of messages that may betransmitted and received through the interface between the SMF and theUPF is limited, the number of filters that may be delivered to the UPFthrough one message is limited. If, in a case that the UPF may bediverse and a sufficient number of filters may not be provided, trafficof the application may not be properly detected, accordingly, anabnormal network situation may be caused.

SUMMARY

Accordingly, the present disclosure proposes a method for addressing theabove-described limitation in providing the user plane function (UPF)with the filter used for detecting traffic of the application by thesession management function (SMF).

According to an aspect of the present disclosure, a method of a firstnetwork entity performing an SMF in a communication system is provided.The method includes obtaining a first filter for a first direction and asecond filter for a second direction, the first filter and the secondfilter being associated with an application, identifying whether thefirst filter is a bidirectional filter based on a result of comparingthe first filter and the second filter, identifying whether a secondnetwork entity performing an UPF supports a function of obtaining thesecond filter, based on the first filter being identified as thebidirectional filter, and transmitting, to the second network entity, afirst message including the first filter and information indicating thatthe first filter is the bidirectional filter, based on identifying thatthe second network entity supports the function of obtaining the secondfilter.

According to an aspect of the present disclosure, a method of a secondnetwork entity performing an UPF in a communication system is provided.The method includes receiving a first message including a first filterfor a first direction associated with an application from a firstnetwork entity performing an SMF, identifying a second filter for asecond direction based on information of the first filter, based on thefirst message indicating that the first filter is a bidirectionalfilter, and detecting traffic of the application based on the firstfilter and the second filter.

According to an aspect of the present disclosure, a first network entitythat performs an SMF in a communication system is provided. The firstnetwork entity includes a transceiver and a controller controlling thetransceiver. The controller is configured to obtain a first filter for afirst direction and a second filter for a second direction, the firstfilter and the second filter being associated with an application,identify whether the first filter is a bidirectional filter based on aresult of comparing the first filter and the second filter, identifywhether a second network entity performing an UPF supports a function ofobtaining the second filter, based on the first filter being identifiedas the bidirectional filter, and transmit, to the second network entity,a first message including the first filter and information indicatingthat the first filter is the bidirectional filter, based onidentification that the second network entity supports the function ofobtaining the second filter.

According to an aspect of the present disclosure, a second networkentity performing an UPF in a communication system is provided. Thesecond network entity includes a transceiver and a controllercontrolling the transceiver. The controller is configured to receive,via the transceiver, a first message including a first filter for afirst direction associated with an application from a first networkentity performing an SMF, identify a second filter for a seconddirection based on information of the first filter, based on the firstmessage indicating that the first filter is a bidirectional filter, anddetect traffic of the application based on the first filter and thesecond filter.

According to the present disclosure, a method is provided for an SMF toefficiently provide the UPF with a filter used to detect traffic of anapplication.

According to an embodiment of the present disclosure, a method isprovided in which the SMF transmits a plurality of packet flowdescriptions (PFDs) to the UPF, each PFD including a plurality offilters for detecting traffic of the application through the PFDmanagement procedure, in a case that the filter may be applied in bothdirections (e.g., uplink direction and downlink direction), and/or theSMF delivers only the PFD including the filter for either direction.Accordingly, the UPF may prevent the transmission and reception ofduplicate information by being able to derive a filter for anotherdirection from a filter for any one direction included in the receivedPFD. Alternatively or additionally, when a network operator sets alarger number of filters for one application and provides them to theUPF, the aspects presented herein may provide for the implementation ofa more efficient system when compared to related communication systems.

The effects that may be obtained from the present disclosure may not belimited to those described herein, and any other effects not mentionedherein are to be clearly understood by those having ordinary knowledgein the art to which the present disclosure belongs, from the followingdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure may become more apparent throughthe following description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a diagram illustrating a structure of a 5th generation (5G)core network 5GC, according to an embodiment of the present disclosure;

FIG. 2A is a diagram illustrating an interface between a sessionmanagement function (SMF) and a packet flow detection function (PFDF),according to an embodiment of the present disclosure;

FIG. 2B is a diagram illustrating a process in which an SMF obtains apacket flow description (PFD) from a PFDF, according to an embodiment ofthe present disclosure;

FIG. 3 is a diagram illustrating a PFD management procedure, accordingto an embodiment of the present disclosure;

FIG. 4 is a diagram illustrating an association procedure between an SMFand a user plane function (UPF), according to an embodiment of thepresent disclosure;

FIG. 5 is a diagram illustrating an operation of an SMF, according to anembodiment of the present disclosure;

FIG. 6 is a diagram illustrating a process in which an SMF provides aPFD including a filter for detecting traffic of an application to a UPF,according to an embodiment of the present disclosure;

FIG. 7 is a diagram illustrating an operation of a UPF, according to anembodiment of the present disclosure;

FIG. 8 is a diagram illustrating a process in which a UPF receives a PFDincluding a filter for detecting traffic of an application from SMF andperforms an application traffic detection operation based on the filter,according to an embodiment of the present disclosure;

FIG. 9 is a diagram illustrating an overall flow of a PFD managementprocedure in which an SMF provides a PFD including a bidirectionalfilter to a UPF, according to an embodiment of the present disclosure;

FIG. 10 is a diagram illustrating a structure of a network entitycapable of performing SMF, according to an embodiment of the presentdisclosure; and

FIG. 11 is a diagram illustrating a structure of a network entitycapable of performing UPF, according to an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

Hereinafter, various embodiments of the present disclosure are describedwith reference to the accompanying drawing.

In the present disclosure, a description of technical content that maybe well known in the technical field to which the present disclosurebelongs and may not be directly related to the present disclosure may beomitted. This is to convey the gist of the present disclosure moreclearly without blurring by omitting an unnecessary description.

For at least similar reasons, some components may be exaggerated,omitted, or schematically illustrated in the accompanying drawings.Alternatively or additionally, the size of each component may not fullyreflect the actual size. The same reference number may be assigned tothe same and/or corresponding components in each drawing.

An advantage and a feature of the present disclosure and a method forachieving them may become apparent with reference to embodimentsdescribed below in detail together with the accompanying drawings.However, the present disclosure is not limited to the embodimentsdisclosed below, but may be implemented in various forms. That is, thefollowing embodiments are provided so that the disclosure may becomplete, and to fully inform those of ordinary skill in the technicalfield to which the present disclosure belongs to the scope of theinvention. The present disclosure may be defined by the scope of theclaims.

It is to be understood that each block of processing flowchart drawingsand combinations of flowchart drawings may be performed by computerprogram instructions.

Since these computer program instructions may be mounted on a processorof a general-purpose computer, a special purpose computer, or otherprogrammable data processing equipment, the instructions performedthrough the processor of the computer or other programmable dataprocessing equipment may generate a mean to perform the functionsdescribed in the flowchart blocks. Since these computer programinstructions may also be stored in a computer-usable and/orcomputer-readable memory that may aim a computer or other programmabledata processing equipment to implement a function in a particularmethod, the instructions stored in the computer-usable and/orcomputer-readable memory may be produced as manufactured items includinginstruction means that may perform functions described in the flowchartblocks. Since the computer program instructions may be mounted on acomputer or other programmable data processing equipment, instructionsfor performing a computer or other programmable data processingequipment by performing a series of operational steps on a computer orother programmable data processing equipment and generating acomputer-executed process may provide steps to execute the functionsdescribed in the flowchart blocks.

In addition, each block may represent a module, segment, or a part ofcode including one or more executable instructions for executing aspecific logical functions. It should also be noted that, in somealternative implementation examples, the functions described in theblocks may occur out of order. For example, two blocks illustrated insuccession may be performed substantially simultaneously, and/or thatthe blocks may be performed in reverse order according to thecorresponding function.

As used herein, the term ‘˜unit’ may refer to software and/or hardwarecomponents such as, but not limited to, a field programmable gate array(FPGA) and an application specific integrated circuit (ASIC), and the‘˜unit’ performs certain roles. However, the ‘˜unit’ may not limited tosoftware and/or hardware. For example, the ‘˜unit’ may be configured tobe in an addressable storage medium and/or may be configured to executeon one or more processors. Thus, as an example, the ‘˜unit’ may comprisesoftware components, obj ect-oriented software components, componentssuch as, but not limited to, class components and task components,processes, functions, attributes, procedures, subroutines, segments ofprogram code, drivers, firmware, microcode, circuits, data, database,data structures, tables, arrays, and variables. The functions providedin components and ‘˜unit’s may be combined into a smaller number ofcomponents and/or ‘˜unit’s and/or may be further separated intoadditional components and ‘˜unit’. Alternatively or additionally, thecomponents and the ‘˜unit’s may be implemented to execute on one or moreprocessors (e.g., central processing units (CPUs)) in a computing deviceand/or storage device (e.g., secure multimedia card (secure MMC)).Alternatively or additionally, in an embodiment, the ‘˜unit’ maycomprise one or more processors.

It is to be understood that singular expressions, such as “above,” “on,”“below,” “under,” “beneath,” and the like, may also include pluralexpressions unless clearly indicated otherwise.

Alternatively or additionally, terms including ordinal numbers, such asfirst, second, and the like may be used to describe various components,but the components may not be limited by the terms. The terms are usedonly for the purpose of distinguishing one component from anothercomponent. For example, a first component may be termed a secondcomponent, and similarly, a second component may be termed a firstcomponent, without departing from the scope of the present disclosure.

In addition, as used herein, the term “and/or” may include a combinationof a plurality of related described items, or any item among a pluralityof related described items. As used herein, each of such phrases as “Aor B,” “at least one of A and B,” “at least one of A or B,” “A, B, orC,” “at least one of A, B, and C,” and “at least one of A, B, or C,” mayinclude any one of, or all possible combinations of the items enumeratedtogether in a corresponding one of the phrases.

In addition, a term used in an embodiment of the present disclosure maybe used only to describe a specific embodiment, and may not be intendedto limit the present disclosure. A singular expression may include aplural expression unless it is explicitly meant differently in thecontext. In the present disclosure, it should be understood that termssuch as “including” or “have” may be intended to designate that afeature, a number, a step, an operation, a component, a part, orcombinations thereof described in the disclosure exist, and may notpre-preclude the presence or additional possibility of one or more otherfeatures or a number, a step, an operation, a component, a part, or anycombination thereof.

In addition, terms such as “associated with” and “associated therewith”and derivatives thereof may refer to terms such as include, be includedwithin, interconnect with, contain, be contained within, connect to orwith, couple to or with, be communicated with, cooperate with,interleave, juxtapose, be proximate to, be bound to or with, have, havea property of, and the like.

In addition, as used herein, conditions described as “equal to orgreater than” may be replaced with “greater than”, conditions describedas “equal to or less than” may be replaced with “less than”, and/orconditions described as “ equal to or greater than or less than” may bereplaced with “ greater than or equal to or less than”.

Reference throughout the present disclosure to “one embodiment,” “anembodiment,” “an example embodiment,” or similar language may indicatethat a particular feature, structure, or characteristic described inconnection with the indicated embodiment is included in at least oneembodiment of the present solution. Thus, the phrases “in oneembodiment”, “in an embodiment,” “in an example embodiment,” and similarlanguage throughout this disclosure may, but do not necessarily, allrefer to the same embodiment.

It is to be understood that the specific order or hierarchy of blocks inthe processes/flowcharts disclosed are an illustration of exemplaryapproaches. Based upon design preferences, it is understood that thespecific order or hierarchy of blocks in the processes/flowcharts may berearranged. Further, some blocks may be combined or omitted. Theaccompanying claims present elements of the various blocks in a sampleorder, and are not meant to be limited to the specific order orhierarchy presented.

Prior to a detailed description of the present disclosure, examples ofan interpretable meaning of several terms used in the present disclosurewere presented. However, it should be noted that the present disclosureis not limited to the interpretation examples presented above.

Hereinafter, a method for providing a bidirectional filter proposed inthe present disclosure and a device capable of performing the same isdescribed.

FIG. 1 is a diagram illustrating a structure of a 5th generation (5G)core network (5GC), according to an embodiment of the presentdisclosure.

Referring to FIG. 1 , the 5GC 100 may provide a user with various typesof services, including voice, between a 5G radio access network (e.g.,next generation-radio access network (RAN) 107) and an external packetdata network. A structure, that may be promulgated by one or more mobilecommunication standards of the Third Generation Partnership Project(3GPP), may define various network functions (NF) in consideration ofnetwork function virtualization (NFV) technology and/or software definednetworking (SDN) in 5GC, and/or configurations of the 5GC 100 with NFs.Consequently, the 5GC 100 may have functions that may be implementedmore flexibly in software, thereby potentially reducing maintenance andrepair equipment costs, when compared to an evolved packet core (EPC) ofa related 4th generation (4G) communication system. The NFs configuringthe 5GC 100 to which the present disclosure may be applied may beexemplified as follows.

As shown in FIG. 1 , the 5GC 100 may include an access and mobilitymanagement function (AMF) 103, a session management function (SMF) 104,an user plane function (UPF) 108, a policy control function (PCF) 102,and an unified data management function (UDM) 101. Although not shown inFIG. 1 , the 5GC 100 may include other NF components such as, but notlimited to, an authentication server function (AUSF), an applicationfunction (AF), a network exposure function (NEF), a network repositoryfunction (NRF), and a network slice selection function (NSSF).

In an embodiment, the AMF 103, the SMF 104, and the UPF 108 may transmitand/or control data by being functionally connected to the RAN 107. Forexample, the AMF 103 and the SMF 104 may process a control plane, andthe UPF 108 may process a user plane. Hereinafter, the SMF 104 and theUPF 108 are described.

The SMF 104 may refer to a NF that may process the control plane. Forexample, the SMF 104 may allocate an internet protocol (IP) address to aterminal (e.g., user equipment (UE) 109) to provide a connection betweenthe terminal and an external data network. Alternatively oradditionally, the SMF 104 may receive an IP address from the UPF 108and/or the external data network and provide the IP address to the UE109. The SMF 104 may generate a protocol data unit (PDU) session tunnelby using a general packet radio service (GPRS) tunneling protocol (GTP)on a next-generation user plane (NG-U) interface between a base stationof the RAN 107 and the UPF 108. That is, the SMF 104 may perform afunction that includes the generating, changing, and/or canceling forthe PDU session between the UE 109 and the data network. Alternativelyor additionally, the SMF 104 may select the UPF 108 to be used by the UE109, may set routing of the UPF 108 so that the UPF 108 may deliverpackets to the destination, and may transmit and/or receive signalingthrough the PCF 102 and the interface to receive an operator policy forquality-of-service (QoS) control. Alternatively or additionally, the SMF104 may provide a control function for charging data collection of theUPF 108, and may support an interface for collecting charging data fromthe UPF 108 and transmitting charging data to charging servers.Alternatively or additionally, the SMF 104 may determine how to providecontinuity of session and service according to the performance ofdownlink data notification by notification of the UPF 108 that packetdata has been received to the downlink and terminal movement, and mayalso support Lawful Interception for a session management event. Likethe AMF 103, the SMF 104 may also utilize the SMF Service by providingNsmf which is a Service Based Interface (SBI), to other certified NFs(Network Functions), according to the introduction of a service-basedstructure of the 5G. The SMF 104 may transmit and receive signaling withthe AMF 103 through the N11 interface, and may transmit and receivesignaling with the UPF 108 through the N4 interface.

In an embodiment, the SMF 104 may be communicatively coupled to a datanetwork (DN) authentication, authorization and accounting (AAA) server(DN-AAA) 105. In such an embodiment, the SMF 104 may access the DN-AAA105 to provide security requirements and/or to provide secureauthentication and authorization methods to the 5GC 100. Alternativelyor additionally, as shown in FIG. 1 , the DN-AAA 105 may becommunicatively coupled to a portal server (data shop) 106.

The UPF 108 may refer to an NF that may process the user plane and/ormay filter packets in units of users in order to transmit packetsreceived from the UE 109 to the data network and/or transmit packetsreceived from the data network to the UE 109. In an embodiment, the UPF108 may serve as a mobility anchor point in a case where the UE 109moves within the 5G system and/or to another system. The UPF 108 mayinform that packets may no longer be received through the correspondingpath by transmitting an ‘End Marker’ to the original base station of theRAN 107. The UPF 108 may allocate a terminal IP address at the requestof the SMF 104. The UPF 108 may perform an application traffic detectionfunction by providing a packet inspection function based on a servicedata flow (SDF) Template and/or a packet flow description (PFD) that mayhave been provided by the SMF 104. Alternatively or additionally, theUPF 108 may perform traffic gating, redirection, and/or steeringaccording to a policy, and/or may provide a lawful intercept (LI)function through user packet collection. The UPF 108 may also providetransmission rate control for uplink and downlink to provide QoS, packetmarking (e.g., differentiated services code point (DSCP)), and/or packetmarking for downlink packets to provide reflective QoS. Alternatively oradditionally, when the UPF 108 receives a packet to be transmitted to aUE 109 in an idle state, the AMF 103 may operate paging for reception ofthe UE 109 through the SMF 104. When the UE 109 accesses the networkafter paging, the UPF 108 may transmit the stored packet to the UE 109.Alternatively or additionally, the UPF 108 may perform a function ofcollecting charging information under the control of the SMF 104. TheUPF 108 may transmit and/or receive signaling with the RAN 107 throughthe N3 interface, may transmit and/or receive signaling with a datanetwork (DN) 111 and/or a portal data network 110 through the N6interface, and may transmit and/or receive signaling with the SMF 104through the N4 interface.

In the above-described 5GC 100, several methods of providing a UPFfilter to detect traffic of an application may be implemented.

A first example method may include a method of providing a filter alongwith a rule (e.g., a packet detection rule (PDR)) related to anoperation of detecting application traffic to the UPF 108 when anIP-connectivity access network (IP-CAN) session or a protocol data unit(PDU) session is generated. Each filter may refer to information (e.g.,an attribute value-pair (AVP)) such as, but not limited to, a packetfilter and a flow description, and the like, that may be used as anapplication filter. The UPF 108 may perform an operation of detectingtraffic of an application based on a provided filter.

A second example method may include a method in which a plurality offilters for applications and an application identifier (ID) indicatingthe corresponding application are provided to the UPF 108, and only theapplication ID corresponding to the filter for detecting traffic issubsequently transmitted when an IP-CAN session or an PDU session isgenerated. The UPF 108 may perform an operation of identifying filterscorresponding to the received application ID among a plurality ofpre-provided filters and detecting the traffic of the correspondingapplication based on identified filter. In an embodiment, the filterprovided to the UPF 108 may be transmitted through the PFD managementrequest message of the PFD management procedure by being included in thePFD. As used herein, the PFD may be referred to as PFD content, but isnot limited thereto, and may be referred to by terms having the same orsimilar meaning.

The first example method may need a plurality of filters to betransmitted to the UPF 108 along with rules whenever a session isgenerated or a new service is added. Consequently, the length of themessage needed to transmit the plurality of filters may increase andexcessive signaling overhead due to frequent message transmission andreception may occur.

Alternatively, according to the second example method, in a case thatthe SMF 104 and the UPF 108 generate a session or a new service isadded, only the application ID may need to be exchanged, and thus, thesize of messages transmitted and received between the SMF 104 and theUPF 108 may be reduced. Thereby, an effect of reducing the load of the5GC network 100 may be obtained. Hereinafter, a method in which the SMF104 provides a plurality of filters used for detecting the traffic ofthe application to the UPF 108 based on the above-described secondmethod is described. However, the present disclosure is not limitedthereto. For example, the present disclosure may also be applied to thefirst example method.

In the above-described second method, a series of processes in which theSMF 104 provides the UPF 108 with a plurality of PFDs each including anapplication ID and a plurality of filters used to detect the traffic ofthe corresponding application may be referred to as the PFD management.Hereinafter, the PFD management is described.

The SMF 104, according to the present disclosure, may obtain the PFDsfrom a NEF before providing the plurality of PFDs to the UPF 108 throughthe PFD management procedure. A process in which the SMF 104 obtains thePFDs from the NEF is described with reference to FIGS. 2A and 2B.

FIG. 2A is a diagram 200 illustrating an interface between an SMF and apacket flow detection function (PFDF), according to an embodiment of thepresent disclosure.

Referring to FIG. 2A, the SMF 104 and the PFDF 202 may transmit and/orreceive signaling through an N29 interface. In the present disclosure,the PFDF 202 may provide the PFDs for at least one application to theSMF 104 at the request of the SMF 104, and the SMF 104 may provide thePFDs to the UPF 108 through the PFD management procedure. Alternativelyor additionally, in a case that there is a change in the PFDs associatedwith a specific application ID, the SMF 104 may subscribe to the PFDF202 to be able to receive notifications or may unsubscribe the PFDF 202to receive no more notifications. Hereinafter, a process in which theSMF 104 obtains the PFD for the application from the PFDF 202 isdescribed with reference to FIG. 2B.

FIG. 2B is a diagram 250 illustrating a process in which an SMF obtainsa PFD from a PFDF according to an embodiment of the present disclosure.

In operation 251, the SMF 104, which may be an NF service consumer, maytransmit a message (e.g., GET request) requesting the PFD for at leastone application ID.

In operation 252, in case that the PFD request is successful, the SMF104 may receive a PFD response including a plurality of PFDs for therequested application ID from the PFDF 202. In an embodiment, the PFDresponse may further include information indicating that the PFD requestof operation 251 was successful. Alternatively or additionally, in acase where the PFD request fails, the SMF 104 may receive an errorindication (e.g., HTTP state code) indicating that the PFD request ofoperation 251 has failed from the PFDF 202.

As described with reference to FIG. 2B, the SMF 104 may obtain the PFDfor the application and may provide the PFD to the UPF 108 through thePFD management procedure.

In an optional or additional embodiment, an operation in which the SMF104 obtains the PFD from the PFDF 202 may not be performed. In such anembodiment, a plurality of filters for the application may bepre-configured in the SMF 104, and the SMF 104 may provide a pluralityof PFDs, each including a plurality of pre-configured filters, to theUPF 108 through the PFD management procedure. For example, in a casewhere a filter for uplink is pre-configured in the SMF 104, the SMF 104may generate (and/or obtain) the PFD including the filter, and providethe PFD to the UPF 108 through the PFD management procedure. As usedherein, the operation of generating (and/or obtaining) the PFD may referto an operation of identifying PFD including a filter according to theformat (e.g., a format described with reference to Table 3 or Table 8)of PFD content. Hereinafter, an embodiment in which the SMF 104 providespre-configured PFDs to the UPF 108 is described.

By referring to FIG. 3 , a method 300 in which the SMF 104 provides thePFD including the filter for detecting application traffic to the UPF108 through the PFD management procedure is described.

FIG. 3 is a diagram illustrating a PFD management procedure, accordingto an embodiment of the present disclosure.

The PFD management procedure may refer to a procedure in which an SMF104, which is a control plane, provides PFDs including a plurality offilters pre-configured for at least one application ID to the UPF 108,which is a user plane, and/or requests the UPF 108 to remove them.

In operation 301, the SMF 104 may determine whether to provision thePFDs for the at least one application to the UPF 108, and/or trigger(e.g., initiate) the PFD management procedure so that the UPF 108 mayremove the PFDs for the at least one application. For example, in a casewhere the SMF 104 receives new PFDs from the PFDF 202 and/or the SMF 104determines that the PFD previously provided to the UPF 108 is no longera valid PFD, the SMF 104 may trigger the PFD management procedure.

In operation 302, in a case where the SMF 104 triggers the PFDmanagement procedure, the SMF 104 may transmit the PFD managementrequest message to the UPF 108. Here, the PFD management request messagemay be configured with the application ID and the PFDs including theplurality of filters for an application corresponding to the applicationID. Alternatively or additionally, in a case where the SMF 104 hasdetermined that the PFD previously provided to the UPF 108 is no longerthe valid PFD, the SMF 104 may empty information on the application IDor the PFDs in the PFD management request message, and transmit the PFDmanagement request message. In an embodiment, in a case where theinformation on the application ID or the PFDs is not present in the PFDmanagement request message, the UPF 108 that received the PFD managementrequest message from the SMF 104 may delete all PFDs for allapplications provided through the previous PFD management procedure.Alternatively or additionally, in a case where the information on atleast one PFD exists in the PFD management request message, the UPF 108may delete all PFDs previously provided for the correspondingapplication and may store all PFDs received in the PFD request message.

In operation 303, in a case where the UPF 108 successfully performs anoperation according to the above-described PFD management requestmessage, the UPF 108 may transmit a PFD management response messageincluding information (e.g., cause “success”) indicating that the PFDmanagement is successful to the SMF 104.

As described with reference to FIG. 3 , the PFD management requestmessage may be transmitted to the UPF 108 for each application. That is,one PFD management request message may be transmitted for eachapplication ID. For example, the PFD management request message of thepresent disclosure may include information in a format as shown in Table1 below.

TABLE 1 PFD Management Request Message Octet 1 and 2 Application ID'sPFDs IE Type = 58 (decimal) Octets 3 and 4 Length = n Information IEelements P Condition/Comment Appl. Type Application M This IE mayidentify the S S S N4 Appli- ID application ID for which xa xb xc cationPFDs may be provisioned ID in the UPF function. PFD context C This IEmay be present — X X X PFD if the PFD needs to be context provisioned inthe UP function. When present, this IE may describe the PFD to beprovisioned in the UPF function. Several IEs with the same IE type maybe present to provision multiple PFDs for this application ID. When thisIE is absent, the UPF function may delete all the PFDs received andstored earlier in the UPF function for this application ID.

According to Table 1, the PFD management request message may include theapplication ID and PFD context associated with PFDs to be provided tothe UPF 108. As used herein, the PFD context may refer to a plurality ofPFDs (e.g., a PFD set) for an application corresponding to theapplication ID. In an embodiment, the PFD context may not be included,and as a result, the UPF 108 may delete all PFDs for the correspondingapplication ID provided through the previous PFD management procedure.That is, in a case where only the application ID is included and the PFDcontext of the PFDs for the application ID is not included, the UPF 108may delete all PFDs previously provided for the correspondingapplication ID.

According to an embodiment, the PFD context of Table 1 may include thePFD content as shown in Table 2 below, wherein the PFD content may referto information that may be included in one PFD. Alternatively oradditionally, providing the PFD may refer to providing the PFD content,and information (and/or properties) of the PFD content that may be usedto detect traffic of the corresponding application. For example, the UPF108 may perform a traffic detection operation based on whetherinformation of the PFD content and traffic of an application match. Thatis, the UPF 108 may identify whether the incoming traffic is detectedbased on whether the incoming traffic matches all properties, at leastone property, or any one property of the PFD content. The information ofthe PFD content may have, for example, a format as shown in Table 3below.

TABLE 2 PFD Context Octet 1 and 2 PFD context IE Type = 59 (decimal)Octets 3 and 4 Length = n Appl. Information S S S N4 IE elements PCondition/Comment xa xb xc Type PFD context M This IE may describe — X XX PFD the PFD to be provisioned context in the UPF function. Several IEswith the same IE type may be present to provision multiple content forthis PFD). (NOTE 1) NOTE 1: The CP function (e.g., the SMF 104 ofFIG. 1) may provision a PFD content including a property with multiplevalues if the UPF 108 supports PFDE function.

TABLE 3 PFD Content Bits Octets 8 7 6 5 4 3 2 1 1 to 2 Type = 61(decimal) 3 to 4 Length = n 5 ADNP AURL AFD DNP CP DN URL FD 6 Spare mto (m + 1) Length of Flow Description (m + 2) to p Flow Description q to(q + 1) Length of URL (q + 2) to r URL s to (s + 1) Length of DomainName (s + 2) to t Domain Name u to (u + 1) Length of Custom PFD Content(u + 2) to v Custom PFD Content w to (w + 1) Length of Domain NameProtocol (w + 2) to x Domain Name Protocol y to (y + 1) Length ofAdditional Flow Description (y + 2) to z Additional Flow Description ato (a + 1) Length of Additional URL (a + 2) to b Additional URL c to(c + 1) Length of Additional Domain Name and Domain Name Protocol (c +2) to d Additional Domain Name and Domain Name Protocol e to (n + 4)These octets may be present only if explicitly specified

As shown in Table 3, the octet 5 of the PFD content may include flagsindicating the type of the PFD content.

For example, each flag of the octet 5 may indicate the followinginformation.

-   -   Bit 1—Flow Description (FD): If the FD bit is set to “1”, the FD        bit may indicate that the length of flow description field and        the flow description field in Table 4 are present in the PFD        content. Alternatively or additionally, the FD bit may indicate        that the PFD content is of the flow description type. That is,        the FD bit being set to “1” may indicate that the flow        description (e.g., filter) is included in the PFD. Alternatively        or additionally, if FD bit is set to “0”, the FD bit may        indicate that the length of flow description field and the flow        description field are not present. That is, when the FD bit is        set to “0”, the FD bit may indicate that the flow description        (e.g., filter) is not included in the PFD.    -   Bit 2—Uniform Resource Locator (URL): If the URL bit is set to        “1”, the URL bit may indicate that the length of URL field and        the URL field of Table 4 are present in the PFD content. That        is, the URL bit being set to “1” may indicate that the PFD        content is of the URL type. Alternatively or additionally, if        the URL bit set to “0”, the URL bit may indicate that the length        of URL field and the URL field are not present in the PFD        content.    -   Bit 3—Domain Name (DN): If the DN bit is set to “1”, the DN bit        may indicate that the length of domain name field and the domain        name field of Table 4 are present in the PFD content. That is,        the DN bit being set to “1” may indicate that the PFD content is        of the domain name type. Alternatively or additionally, if the        DN bit set to “0”, the DN bit may indicate that the length of        domain name field and the domain name field are not present in        the PFD content.    -   Bit 4—Custom PFD Content (CP): If the CP bit is set to “1”, the        CP bit may indicate that the length of custom content field and        the custom PFD content field of Table 4 are present in the PFD        content. That is, the CP bit being set to “1” may indicate that        the PFD content is of the custom PFD content type. Alternatively        or additionally, if the CP bit set to “0”, the CP bit may        indicate that the length of custom content field and the custom        PFD content field are not present in the PFD content.    -   Bit 5—Domain Name Protocol (DNP): If the DNP bit is set to “1”,        the DNP bit may indicate that the length of domain name protocol        field and the domain name protocol field of Table 4 are present        in the PFD content. That is, the DNP bit being set to “1” may        indicate that the PFD content is of the domain name protocol        type. Alternatively or additionally, if the DNP bit set to “0”,        the DNP bit may indicate that the length of domain name protocol        field and the domain name protocol field are not present in the        PFD content.    -   Bit 6—Additional Flow Description (AFD): If the AFD bit is set        to “1”, the AFD bit may indicate that the length of additional        flow description field and the additional flow description field        of Table 4 are present in the PFD content. That is, the AFD bit        being set to “1” may indicate that the PFD content is of the        additional flow description type. Alternatively or additionally,        if the AFD bit is set to “0”, the AFD bit may indicate that the        length of additional flow description field and the additional        flow description field are not present in the PFD content.    -   Bit 7—Additional URL (AURL): If the AURL bit is set to “1”, the        AURL bit may indicate that the length of additional URL field        and the additional URL field of Table 4 are present in the PFD        content. That is, the AURL bit being set to “1” may indicate        that the PFD content is of the additional URL type.        Alternatively or additionally, if the AURL bit is set to “0”,        the AURL bit may indicate that the length of additional URL        field and the additional URL field are not present in the PFD        content.    -   Bit 7—Additional Domain Name and Domain Name Protocol (ADNP): If        the ADNP bit is set to “1”, the ADNP bit may indicate that the        length of additional domain name and domain name protocol field        and the additional domain name and domain name protocol field of        Table 4 are present in the PFD content. That is, the ADNP bit        being set to “1” may indicate that the PFD content is of the        additional domain name and domain name protocol type.        Alternatively or additionally, if the ADNP bit is set to “0”,        the ADNP bit may indicate that the length of additional domain        name and domain name protocol field and the additional domain        name and domain name protocol field are not present in the PFD        content.

That is, whether to support the above-described PFD management proceduremay correspond to an option of the SMF 104 and the UPF 108. Thus, in acase where the UPF 108 may support the PFD management procedure, the UPF108 may inform the SMF 104 that the UPF 108 may support the PFDmanagement procedure. For example, the UPF 108 may inform the SMF 104that the UPF 108 may support the PFD management procedure by performingan N4 association setup procedure between the SMF 104 and the UPF 108,as described with reference to FIG. 4 .

FIG. 4 is a diagram illustrating an association procedure between an SMFand a UPF according to an embodiment of the present disclosure.

The N4 association setup procedure 400 performed between the SMF 104 andthe UPF 108 may refer to a series of procedures performed to enable theSMF 104 to establish an N4 session using the UPF 108 resources bygenerating an N4 association between the SMF 104 and the UPF 108.

Referring to FIG. 4 , in operation 401, the SMF 104 may transmit an N4association setup request (or may be referred to using various termssuch as, but not limited to, an N4 association setup request message, anassociation setup request, an association setup request message, and thelike) to the UPF 108.

In operation 402, in response to the N4 association setup requesttransmitted in operation 401, the SMF 104 may receive an N4 associationsetup response (or may be referred to using various terms such as an N4association setup response message, an association setup response, anassociation setup response message, and the like) from the UPF 108. Inan embodiment, the N4 association setup response message may includeinformation on features supported by the UPF 108. For example, the N4association setup response message may follow a format as shown in Table4 below.

TABLE 4 N4 Association Setup Response Message Bits Octets 8 7 6 5 4 3 21 1 to 2 Type = 43 (decimal) 3 to 4 Length = n 5 to 6 Supported-Features7 to 8 Additional Supported-Features 1 9 to 10 AdditionalSupported-Features 2 11 to (n + 4) These octets may be present only ifexplicitly specified

In Table 4, the function supported by the UPF 108 may be indicated basedon the bits set in the supported-features field corresponding to octets5 to 6, the additional supported-features 1 field corresponding tooctets 7 to 8, and the additional supported-features 2 fieldcorresponding to octets 9 to 10. For example, by setting six (6) bits ofthe supported-features field corresponding to octet 5 to “1”, thesupported-features field may indicate that the UPF 108 supports afunction (e.g., a PFD management (PFDM) feature) capable of performing aPFD management procedure. As shown in FIG. 4 , the SMF 104 may initiatethe N4 association setup procedure as an example, but the presentdisclosure is not limited thereto. That is, the UPF 108 may initiate theN4 association setup procedure. In such an embodiment, the UPF 108 mayinclude information on features supported by the UPF 108, in the N4association setup request message, and may transmit the N4 associationsetup request message to the SMF 104.

In an embodiment, the PFD management request message and/or the PFDmanagement response message may be transmitted and/or received throughan N4 interface using a packet forwarding control protocol (PFCP) basedon a user datagram protocol (UDP). Assuming that a maximum length of aUDP payload is 65,535 bytes, which may correspond to the maximum valueof a length field having 16 bits, there is may be restriction that thepayload of the PFD management request message transmitted through the N4interface using the PFCP based on UDP needs to be within about 60,000bytes. For example, in a case where a network operator sets hundreds ormore filters for one application and wants to provide PFDs, in whicheach PFD includes the filters, to the UPF 108, the payload length of thePFD management request message including the PFDs may need to be lessthan the maximum length of the UDP payload. That is, in a case where thenetwork operator wants to provide the UPF 108 with the PFD (e.g., anIPv6 flow description type PFD) that includes a filter that includesboth the source and destination of the packet, as shown in Table 5below, the number of PFDs for one application that may be included inthe PFD management request message may be limited to about 400.

TABLE 5 Example PFD “permit out 17 from2132:5678:9abc:def0:2132:5678:9abc:def0 65530-65534 to3132:5678:9abc:def0:3132:5678:9abc:def0 65530-65534”

In an optional or additional embodiment, two single-directional PFDs,each including a filter for an Uplink direction and a filter for aDownlink direction, may be provided to the UPF 108 together. Forexample, as shown in Table 6, the PFD including the filter for theUplink and the PFD including the filter for the Downlink may be includedin the PFD management request messages respectively and may be providedto the UPF 108.

TABLE 6 Example PFD Uplink: “permit in 17 from any to 10.1.1.10 8080”Downlink: “permit out 17 from 10.1.1.10 8080 to any”

In an embodiment, the filters of Table 6 may be different only in thedirection, but other information, such as, but not limited to, IPProtocol, Source/Destination IP Address, Source/Destination Port Number,and the like, may be the same. Thus, in such an embodiment, providingboth the filter for the Uplink and the filter for the Downlink to theUPF 108 may include providing redundant information, and thereby, thelength resource of limited messages may be used inefficiently.

That is, if a filter for one direction is provided to the UPF 108, theUPF 108 may derive a filter for the other direction based on the filterprovided. Consequently, the number of PFDs that may be included in thePFD management request may be reduced, and thereby, the above-describedmessage length limitation may be addressed. Alternatively oradditionally, an improved application traffic detection may be performedby enabling an increased quantity and/or diversity of filters to be setfor the corresponding application. A method by which the UPF 108 mayreceive only the PFD including a filter for any one direction and mayderive a filter for the other direction is described. In the presentdisclosure, the bidirectional filter may be referred to by abidirectional flow description and/or a term having the same and/orsimilar meaning, and may refer to a filter included in the PFD accordingto a format as shown in Table 8.

In an embodiment, instead of providing the UPF 108 with bothsingle-directional PFDs including the filter for Uplink and the filterfor Downlink, respectively, the SMF 104 may provide the UPF 108 with thePFD including the filter for any one direction and information (e.g., aspecific indicator) indicating that the filter may be applied in bothdirections. Based on the UPF 108 provided with the PFD and the filterfor any one direction included in the PFD, a filter in the oppositedirection may be identified (and/or derived) and may be used in thetraffic detection operation of the application. In an optional oradditional embodiment, the UPF 108 may perform an operation ofidentifying (and/or deriving) the filter of the opposite direction basedon the filter for any one direction included in the PFD, which may bereferred to as a bidirectional (BIDIR) function.

In an embodiment, the operation the SMF 104 of the control plane and theUPF 108 of the user plane may need to be changed in order to perform theBIDIR function. That is, support of the BIDIR function by the UPF 108may be optional. Thus, the UPF 108, according to an embodiment, maynotify the SMF 104 whether the UPF 108 supports the BIDIR function. Forexample, the UPF 108 may notify the SMF 104 in a N4 association setupprocedure between the SMF 104 and the UPF 108 (e.g., as described withreference to FIG. 4 ), the UPF 108 may include information on functionssupported by the UPF 108 in the N4 association setup request message(e.g., in a case where the N4 association setup procedure is initiatedby the UPF 108) and/or the N4 association setup response message (e.g.,in a case where the N4 association setup procedure is initiated by theSMF 104), which may be transmitted to the SMF 104. For another example,the UPF 108 may notify the SMF 104 by including information on functionssupported by the UPF 108 in the N4 association setup request messageand/or the N4 association setup response message according to a formatas shown in Table 7 below. In an embodiment, the format shown in Table 7may be a vendor-specific information element format that may be definedby agreement between vendors

According to Table 7, in a case where bit 1 of the field correspondingto octet 7 is set to “1”, the field may indicate that the UPF 108supports the BIDIR function.

The SMF 104 may identify whether a filter to be provided to the UPF 108that may be applied in bi-directions. Alternatively or additionally,when the filter may be applied in bi-directions, the SMF 104 mayidentify that the UPF 108 supports the BIDIR function. In a case wherethe UPF 108 supports the BIDIR function, the SMF 104 may provide the UPF108 with the PFD including the filter and an indicator that the filtermay be applied in bi-directions. Alternatively or additionally, in acase where the PFD including a filter to which the SMF 104 may beapplied in bi-directions is provided to the UPF 108, information (e.g.,PFD content) that may be included in the PFD may follow a format asshown in Table 8 below.

According to Table 8, the bit 4 of octet 5 being set to “1” may indicatethat a custom PFD content field exists , that a type indicating that thefilter included in the corresponding PFD is a filter that may be appliedin this bi-directions is designated in the field of Octet 9 where thePFD content begins. In such an example, the PFD content may provide theUPF 108 with the PFD including a filter for any one direction (e.g.,uplink and/or downlink) in a subsequent field (e.g., octets 10 to n).The UPF 108 may identify whether the filter included in the received PFDmay be applied in bi-directions based on information included in thecorresponding PFD (e.g., information on the type of the PFD or anindicator), and according to the information, the UPF 108 may perform anapplication traffic detection operation. Hereinafter, the operation ofthe SMF 104 and the UPF 108 operated according to a method for providingthe PFD providing is described with reference to FIGS. 5 to 9 .

FIG. 5 is a diagram illustrating a method 500 of an SMF, according to anembodiment of the present disclosure.

Referring to FIG. 5 , in operation 501, the SMF 104 may identify whetherthe filter for the application is for an Uplink direction, a Downlinkdirection, and/or bi-directions. Alternatively or additionally, the SMF104 may identify whether the filter may be applied in bi-directions(whether the filter is a bidirectional filter). For example, in a casewhere the filter is pre-configured for bi-directions, or in a case wherethe filter for the Uplink direction and the filter for the Downlinkdirection have opposite sources and destinations, and other information(e.g., IP Protocol, IP address, port) is the same, the SMF 104 mayidentify that the filter (and/or the filter for the Downlink direction)for the Uplink direction may be applied in bi-directions. That is, thefilter may be applied in bi-directions when the same filter as thefilter for the opposite direction may be obtained as a result ofswitching only source and destination information among the informationof the corresponding filter. For example, in a case where the filter forthe Uplink direction (hereinafter referred to as a first filter) and thefilter for the Downlink direction (hereinafter referred to as a secondfilter) are included in the PFD, and as a result of switching only thesource and destination information among the information of the firstfilter, the same filter as the second filter is obtained (and/orgenerated), the SMF 104 may identify that the first filter may beapplied in bi-directions. Alternatively or additionally, in a case wherea filter different from the second filter is obtained as a result ofswitching only the source and destination information among theinformation of the first filter, the SMF 104 may identify that the firstfilter cannot be applied in bi-directions. Alternatively oradditionally, identifying whether the filter may be applied inbi-directions in the present disclosure may refer to identifying whetherthe corresponding filter is a bidirectional filter.

In operation 502, in a case where the SMF 104 has identified that thefilter may be applied in bi-directions, the SMF 104 may identify whetherthe UPF 108 supports the BIDIR function capable of deriving the filterfor another direction from the filter for any one direction. Forexample, the SMF 104 may identify whether the UPF 108 supports the BIDIRfunction based on information on the functions supported by the UPF 108received in the N4 association setup procedure with the UPF 108, asdescribed with reference to FIG. 4 .

In operation 504, if in a case where the UPF 108 does not support theBIDIR function, the SMF 104 may identify (and/or generate, obtain) twoPFDs each including the filter for the Uplink direction and the filterfor the Downlink direction. Here, the PFD may follow the format shown inTable 3. Alternatively or additionally, if in a case where the UPF 108supports the BIDIR function, the SMF 104 may identify (and/or generate,obtain) the PFD including the filter for any one direction andinformation (e.g., type information, indicator) that the filter may beapplied in bi-directions. Here, the PFD may follow the format shown inTable 8.

In operation 505, the SMF 104 may transmit the PFD identified inoperation 504 to the UPF 108 by including the PFD in the managementrequest message.

In some embodiments, operations 501 to 505 of FIG. 5 may be performedsimultaneously, and/or some of the operations may be omitted.

FIG. 6 is a diagram illustrating a process 600 in which an SMF 104,according to an embodiment of the present disclosure, may provide a PFDincluding a filter for detecting traffic of an application to a UPF 108.

Referring to FIG. 6 , in operation 601, the SMF 104 may operate byprocessing the control plane of a 5GC (e.g., 5GC 100 of FIG. 1 ).

In operation 602, the SMF 104 may identify whether a filter for theapplication is for an Uplink direction, a Downlink direction, orbi-directions, and/or may identify whether the filter may be applied inbi-directions. For example, in a case where the filter is pre-configuredfor bi-directions, or in a case where the filter for the Uplinkdirection and the filter for the Downlink direction have oppositesources and destinations, and other information (e.g., IP Protocol, IPaddress, Port) is the same, the SMF 104 may identify that the filter forthe Uplink direction (and/or the filter for the Downlink direction) maybe applied in bi-directions. In a case where the SMF 104 identifies thatthe filter cannot be applied in bi-directions in operation 602 (NO inoperation 602), in operation 603, the SMF 104 may identify (and/orgenerate, obtain) two PFDs each including the filter for the Uplinkdirection and the filter for the Downlink direction. Here, the PFD mayfollow the format shown in Table 3.

Alternatively or additionally, in a case where the SMF 104 identifiesthat the filter may be applied in bi-directions in operation 602 (YES inoperation 602), in operation 604, the SMF 104 may identify whether theUPF 108 supports the BIDIR function capable of deriving the filter foranother direction from the filter for any one direction. For example,the SMF 104 may identify whether the UPF 108 supports the BIDIR functionbased on information on the functions supported by the UPF 108 receivedin the N4 association setup procedure with the UPF 108.

In a case where the SMF 104 identifies that the UPF 108 supports theBIDIR function in operation 604 (YES in operation 604), in operation605, the SMF 104 may identify (and/or generate, obtain) the PFDincluding the filter for any one direction and information (e.g., typeinformation, indicator) that may be applied in bi-directions. Here, thePFD may follow the format shown in Table 8.

In a case where the SMF 104 identifies that the UPF 108 does not supportthe BIDIR function in operation 604, in operation 606, the SMF 104 mayidentify (and/or generate, obtain) two PFDs each including the filterfor the Uplink direction and the filter for the Downlink direction.Here, the PFD may follow the format shown in Table 3.

In operation 607, the SMF 104 may transmit the PFD to the UPF 108 byincluding the PFD identified in the operation 603, the operation 605, orthe operation 606 in the PFD management request message.

In an embodiment, operations 602 to 607 of FIG. 6 may be performedsimultaneously, and/or some operations may be omitted.

FIG. 7 is a diagram illustrating an operation 700 of a UPF 108,according to an embodiment of the present disclosure.

Referring to FIG. 7 , in operation 701, the UPF 108 may receive a PFDmanagement request message including a plurality of PFDs for anapplication from the SMF 104.

In operation 702, the UPF 108 may identify whether the filter may beapplied in bi-directions based on information (e.g., type information,indicator) included in the received PFD. For example, in a case wherethe received PFD includes the filter according to the format shown inTable 3, the UPF 108 may identify that the filter is a filter forsingle-direction that cannot be applied in bi-directions. Alternativelyor additionally, in a case where the received PFD includes the filteraccording to the format shown in Table 8, the UPF 108 may identify thatthe filter may be applied in bi-directions.

In a case where the UPF 108 identifies that the received filter may beapplied in bi-directions in operation 701, in operation 703, the UPF 108may derive (and/or obtain, generate) the filter for another (e.g.,opposite) direction from the filter for any one direction, and may applythe two filters as filters for detecting traffic of the application. Forexample, in a case where the UPF 108 identifies that the received filteris a filter for an Uplink direction and may be applied in bi-directions,the UPF 108 may derive a filter for a Downlink direction from thefilter, and may apply the received filter and the derived filter as afilter for detecting traffic of the application. In an embodiment, anoperation of deriving the filter for another direction from the filterfor any one direction may refer to an operation of identifying a filterin a direction different from the corresponding filter by switching thesource and destination of the filter.

In operation 704, the UPF 108 may transmit a PFD management responsemessage including information indicating that the PFD management hassucceeded to the SMF 104, in response to the PFD management requestmessage received in operation 701.

In operation 705, the UPF 108 may perform an operation of detectingtraffic of the application based on the identified filters. For example,the UPF 108 may identify whether traffic of an application matching theidentified filter has been generated (e.g., detected, received).

In an embodiment, operations 701 to 705 of FIG. 7 may be performedsimultaneously, and/or some operations may be omitted.

FIG. 8 is a diagram 800 illustrating a process in which a UPF 108,according to an embodiment, receives a PFD including a filter fordetecting traffic of an application from SMF 104 and performs anapplication traffic detection operation based on the filter.

Referring to FIG. 8 , in operation 801, the UPF 108 may receive a PFDmanagement request message including a plurality of PFDs for theapplication from the SMF 104.

In operation 802, the UPF 108 may identify whether the filter may beapplied in bi-directions based on information (e.g., type information,indicator) included in the received PFD. For example, in a case wherethe received PFD includes the filter according to the format shown inTable 3, the UPF 108 may identify that the filter is a filter forsingle-direction that cannot be applied in bi-directions. Alternativelyor additionally, in a case where the received PFD includes the filteraccording to the format shown in Table 8, the UPF 108 may identify thatthe filter may be applied in bi-directions.

In a case where the UPF 108 identifies that the filter received inoperation 801 may only be applied in single-direction (e.g., Uplinkdirection and/or Downlink direction) or in a case where the UPF 108 doesnot support the BIDIR function (NO in operation 802), in operation 804,the UPF 108 may apply a single-directional filter as a filter fordetecting traffic of the application.

In a case where the UPF 108 identifies that the filter received inoperation 801 may be applied in bi-directions (YES in operation 802), inoperation 803, the UPF 108 may derive the filter for another directionfrom the filter for any one direction, and may apply the two filters asfilters for detecting traffic of the application. For example, in a casewhere the UPF 108 identifies that the received filter is a filter forthe Uplink direction and may be applied in bi-directions, the UPF 108may derive a filter for the Downlink direction from the Uplink filter,and may apply the received filter and the derived filter as the filterfor detecting traffic of the application. In an embodiment, an operationof deriving the filter for another direction from the filter for any onedirection may refer to an operation of identifying a filter in adirection different from the corresponding filter by switching thesource and destination of the filter.

In operation 805, the UPF 108 may transmit a PFD management responsemessage including information indicating that the PFD management hassucceeded to the SMF 104 in response to the PFD management requestmessage received in operation 801.

In operation 806, the UPF 108 may perform an operation of detectingtraffic of the application based on the filter identified in operation803 or in operation 804. For example, the UPF 108 may identify whethertraffic of the application matching the identified filter has beengenerated. In an embodiment, operations 801 to 806 of FIG. 8 may beperformed simultaneously, and/or some of the operations may be omitted.

FIG. 9 is a diagram 900 illustrating an overall flow of a PFD managementprocedure in which an SMF 104 provides a PFD including a bidirectionalfilter to a UPF 108, according to an embodiment of the presentdisclosure.

Referring to FIG. 9 , in operation 901, the SMF 104 and the UPF 108 mayperform the N4 association setup procedure, as described with referenceto FIG. 4 . In the N4 association setup procedure, which may beinitiated by the SMF 104 and/or the UPF 108, the UPF 108 may transmitinformation (e.g., the PFDM function and/or the BIDIR function) on thefunctions supported by the UPF 108 to the SMF 104 by including theinformation in an N4 association setup request message (e.g., in a casewhere the N4 association setup procedure is initiated by the UPF 108)and/or an N4 association setup response message (e.g., in a case wherethe N4 association setup procedure is initiated by the SMF 104).

In operation 902, the SMF 104 may identify whether a filter for theapplication is for an Uplink direction, a Downlink direction, orbi-directions, and/or may identify whether the filter may be applied inbi-directions. For example, in a case where the filter is pre-configuredfor bi-directions, or in a case where the filter for the Uplinkdirection and the filter for the Downlink direction have oppositesources and destinations, and other information (e.g., IP Protocol, IPaddress, Port) is the same, the SMF 104 may identify that the packetfilter (or the packet filter for the Downlink direction) for the Uplinkdirection may be applied in bi-directions.

In operation 903, in a case where the SMF 104 identifies that the filterobtained in operation 901 may be applied in bi-directions, the SMF 104may identify whether the UPF 108 supports the BIDIR function capable ofderiving the filter for another direction from the filter for any onedirection. For example, the SMF 104 may identify whether the UPF 108supports the BIDIR function based on information on the functionssupported by the UPF 108 received in the N4 association setup procedurewith the UPF 108.

In a case where the SMF 104 identifies that the UPF 108 supports theBIDIR function in operation 903, in operation 904, the SMF 104 mayidentify (and/or generate, obtain) the PFD including the filter for anyone direction and information (e.g., type information, indicator) thatthe filter may be applied in bi-directions. Here, the PFD may follow theformat shown in Table 8.

In operation 905, the SMF 104 may transmit the identified PFD to the UPF108 by including identified PFD in the PFD management request message.

In operation 906, the UPF 108 may identify whether the filter may beapplied in bi-directions based on information (e.g., type information,indicator) included in the received PFD. For example, in a case wherethe received PFD includes the filter according to the format shown inTable 3, the UPF 108 may identify that the filter is a filter forsingle-direction that cannot be applied in bi-directions. Alternativelyor additionally, in a case where the received PFD includes the filteraccording to the format shown in Table 8, the UPF 108 may identify thatthe filter may be applied in bi-directions.

In operation 907, in a case where the UPF 108 has identified that thereceived filter may only be applied in single-direction (e.g., Uplinkdirection or Downlink direction), the single-directional filter may beapplied as a filter for detecting traffic of the application.Alternatively or additionally, in a case where the UPF 108 hasidentified that the received filter may be applied in bi-directions, theUPF 108 may derive the filter for another direction from the filter forany one direction, and may apply the two filters as filters fordetecting traffic of the application.

In operation 908, the UPF 108 may transmit a PFD management responsemessage including information indicating that the PFD management hassucceeded to the SMF 104 in response to the PFD management requestmessage received in operation 905.

In operation 909, the UPF 108 may perform an operation of detectingtraffic of the application based on the identified filter. For example,the UPF 108 may identify whether traffic of the application matching theidentified filter has generated.

In an embodiment, the UPF 108 may have received a PFD includingbidirectional filters from which the UPF 108 may derive the filter foranother direction from the received filter for any one direction.Consequently, a message length limitation problem may be addressed bypreventing the inclusion of redundant information and/or informationthat may be derived from information included in message transmissionsto the UPF 108. Furthermore, a network operator may set a larger numberof filters for one application and may provide the PFD including alarger and/or more diverse set of filters to the UPF 108, so that a moreefficient system may be implemented, when compared to relatedcommunication systems.

FIG. 10 is a diagram illustrating a structure of a network entitycapable of performing SMF, according to an embodiment of the presentdisclosure.

Referring to FIG. 10 , the network entity 1000 may be capable ofperforming the SMF, according to an embodiment. That is, the networkentity 1000 may include or may be similar in many respects to the SMF104 described above with reference to FIGS. 1 to 9 and may includeadditional features not mentioned above. In an embodiment, the networkentity 1000 may include a transceiver 1005, a controller 1010, and amemory 1015.

The transceiver 1005 may transmit and/or receive signals to and/or fromanother network entity. For example, the transceiver 1005 may transmitand/or receive signals to and/or from another network entity through anetwork interface such as a cable and the like. For example, thetransceiver may transmit system information to a base station of the RAN107 and may transmit a synchronization signal or a reference signal.

The controller 1010 may control the overall operation of the SMF 104,according to the embodiment.

The memory 1015 may store at least one of information transmitted andreceived through the transceiver 1005 and information generated throughthe controller 1010.

The number and arrangement of components of the network entity 1000shown in FIG. 10 are provided as an example. In practice, there may beadditional components, fewer components, different components, ordifferently arranged components than those shown in FIG. 10 .Furthermore, two or more components shown in FIG. 10 may be implementedwithin a single component, or a single component shown in FIG. 10 may beimplemented as multiple, distributed components. Alternatively oradditionally, a set of (one or more) components shown in FIG. 10 may beintegrated with each other, and/or may be implemented as an integratedcircuit, as software, and/or a combination of circuits and software.

FIG. 11 is a diagram illustrating a structure of a network entitycapable of performing UPF, according to an embodiment of the presentdisclosure.

Referring to FIG. 11 , the network entity 1100 capable of performingUPF, according to an embodiment. That is, the network entity 1100 mayinclude or may be similar in many respects to the UPF 108 describedabove with reference to FIGS. 1 to 9 and may include additional featuresnot mentioned above. In an embodiment, the network entity 1100 mayinclude a transceiver 1105, a controller 1110, and a memory 1115.

The transceiver 1105 may transmit and/or receive signals to and/or fromanother network entity. For example, the transceiver 1105 may transmitand/or receive signals to and/or from another network entity through anetwork interface such as, but not limited to, a cable and the like. Forexample, the transceiver may transmit system information to a basestation and/or may transmit a synchronization signal or a referencesignal.

The controller 1110 may control the overall operation of the UPF 108,according to an embodiment.

The memory 1115 may store at least one of information transmitted andreceived through the transceiver 1105 and information generated throughthe controller 1110.

The number and arrangement of components of the network entity 1100shown in FIG. 11 are provided as an example. In practice, there may beadditional components, fewer components, different components, ordifferently arranged components than those shown in FIG. 11 .Furthermore, two or more components shown in FIG. 11 may be implementedwithin a single component, or a single component shown in FIG. 11 may beimplemented as multiple, distributed components. Alternatively oradditionally, a set of (one or more) components shown in FIG. 11 may beintegrated with each other, and/or may be implemented as an integratedcircuit, as software, and/or a combination of circuits and software.

The methods proposed in the present disclosure may be executed bycombining some or all of the content included in each embodiment withinthe scope of the present disclosure without impairing the essence of thepresent disclosure.

It is to be understood that the embodiments of the present disclosureare merely examples provided to explain the technical content of thepresent disclosure and help understand the present disclosure, and arenot intended to limit the scope of the present disclosure. That is, itis understood that a person having ordinary knowledge in the technicalfield to which the present disclosure belongs may implement modifiedexamples based on the technical idea of the present disclosure withoutdeparting from the scope of the present disclosure.

What is claimed is:
 1. A method of a first network entity performing asession management function (SMF) in a communication system, comprising:obtaining a first filter for a first direction and a second filter for asecond direction, the first filter and the second filter beingassociated with an application; identifying whether the first filter isa bidirectional filter based on a result of comparing the first filterand the second filter; identifying whether a second network entityperforming a user plane function (UPF) supports a function of obtainingthe second filter, based on the first filter being identified as thebidirectional filter; and transmitting, to the second network entity, afirst message comprising the first filter and information indicatingthat the first filter is the bidirectional filter, based on identifyingthat the second network entity supports the function of obtaining thesecond filter.
 2. The method of claim 1, further comprising:transmitting, to the second network entity, an association setup requestmessage; and receiving, from the second network entity in response tothe association setup request message, an association setup responsemessage comprising functional information of the second network entity,wherein the functional information indicates whether the second networkentity supports the function of obtaining the second filter.
 3. Themethod of claim 1, further comprising: determining, based on the resultof the comparing of the first filter and the second filter, that firstsource information and first destination information of the first filterrespectively correspond to second source information and seconddestination information of the second filter; and identifying that thefirst filter is the bidirectional filter based on the determining,wherein the second filter has been obtained by the second network entitybased on the first filter being identified as the bidirectional filter,and wherein the first filter and the second filter are configured todetect traffic of the application.
 4. The method of claim 1, furthercomprising: transmitting, to the second network entity, a second messagecomprising the first filter and the second filter, based on the firstfilter not being identified as the bidirectional filter.
 5. The methodof claim 1, further comprising: transmitting, to the second networkentity, a second message comprising the first filter and the secondfilter to the second network entity, based on identifying that thesecond network entity does not support the function of obtaining thesecond filter.
 6. A method of a second network entity performing a userplane function (UPF) in a communication system, comprising: receiving afirst message comprising a first filter for a first direction associatedwith an application from a first network entity performing a sessionmanagement function (SMF); identifying a second filter for a seconddirection based on information of the first filter, based on the firstmessage indicating that the first filter is a bidirectional filter; anddetecting traffic of the application based on the first filter and thesecond filter.
 7. The method of claim 6, further comprising: receiving,from the first network entity, an association setup request message; andtransmitting, to the first network entity in response to the associationsetup request message, an association setup response message comprisingfunctional information of the second network entity, wherein thefunctional information indicates that the second network entity supportsa function of identifying the second filter based on the first filter.8. The method of claim 6, wherein: the first filter has been identifiedas the bidirectional filter based on a determination, based on a resultof a comparison of the first filter and the second filter, that firstsource information and first destination information of the first filterrespectively correspond to second source information and seconddestination information of the second filter, wherein the second filterhas been obtained by the second network entity based on the first filterbeing identified as the bidirectional filter, and wherein the firstfilter and the second filter are configured to detect the traffic of theapplication.
 9. The method of claim 6, further comprising: receiving,from the first network entity, a second message comprising the firstfilter and the second filter, based on the first filter not beingidentified as the bidirectional filter.
 10. The method of claim 6,wherein the detecting of the traffic of the application comprisesidentifying whether the traffic matches at least one of the first filterand the second filter.
 11. A first network entity that performs asession management function (SMF) in a communication system, the firstnetwork entity comprising: a transceiver; and a controller controllingthe transceiver, wherein the controller is configured to: obtain a firstfilter for a first direction and a second filter for a second direction,the first filter and the second filter being associated with anapplication; identify whether the first filter is a bidirectional filterbased on a result of comparing the first filter and the second filter;identify whether a second network entity performing a user planefunction (UPF) supports a function of obtaining the second filter, basedon the first filter being identified as the bidirectional filter; andtransmit, to the second network entity, a first message comprising thefirst filter and information indicating that the first filter is thebidirectional filter, based on identification that the second networkentity supports the function of obtaining the second filter.
 12. Thefirst network entity of claim 11, wherein the controller is furtherconfigured to: transmit, via the transceiver to the second networkentity, an association setup request message; and receive, via thetransceiver from the second network entity in response to theassociation setup request message, an association setup response messagecomprising functional information of the second network entity, whereinthe functional information indicates whether the second network entitysupports the function of obtaining the second filter.
 13. The firstnetwork entity of claim 11, wherein the controller is further configuredto: determine, based on the result of comparing of the first filter andthe second filter, that first source information and first destinationinformation of the first filter respectively correspond to second sourceinformation and second destination information of the second filter; andidentify that the first filter is the bidirectional filter based on thedetermination, wherein the second filter has been obtained by the secondnetwork entity based on the first filter having been identified as thebidirectional filter, and wherein the first filter and the second filterare configured to detect traffic of the application.
 14. The firstnetwork entity of claim 11, wherein the controller is further configuredto: transmit, via the transceiver to the second network entity, a secondmessage comprising the first filter and the second filter, based on theidentification that the first filter is not the bidirectional filter.15. The first network entity of claim 11, wherein the controller isfurther configured to: transmit, via the transceiver to the secondnetwork entity, a second message comprising the first filter and thesecond filter, based on the identification that the second networkentity does not support the function of obtaining the second filter. 16.A second network entity performing a user plane function (UPF) in acommunication system, comprising: a transceiver; and a controllercontrolling the transceiver, wherein the controller is configured to:receive, via the transceiver, a first message comprising a first filterfor a first direction associated with an application from a firstnetwork entity performing a session management function (SMF); identifya second filter for a second direction based on information of the firstfilter, based on the first message indicating that the first filter is abidirectional filter; and detect traffic of the application based on thefirst filter and the second filter.
 17. The second network entity ofclaim 16, wherein the controller is further configured to: receive, fromthe first network entity, an association setup request message; andtransmit, to the first network entity in response to the associationsetup request message, an association setup response message comprisingfunctional information of the second network entity, wherein thefunctional information indicates that the second network entity supportsa function of identifying the second filter based on the first filter.18. The second network entity of claim 16, wherein: the first filter hasbeen identified as the bidirectional filter based on a determination,based on a result of a comparison of the first filter and the secondfilter, that first source information and first destination informationof the first filter respectively correspond to second source informationand second destination information of the second filter, wherein thesecond filter has been obtained by the second network entity based onthe first filter being identified as the bidirectional filter, andwherein the first filter and the second filter are configured to detectthe traffic of the application.
 19. The second network entity of claim16, wherein the controller is further configured to: receive, from thefirst network entity, a second message comprising the first filter andthe second filter, based on the first filter not being identified as thebidirectional filter.
 20. The second network entity of claim 16, whereinthe controller is further configured to identify whether the trafficmatches at least one of the first filter and the second filter.